Abstract:

A punch press tool for stamping successive multicharacter impressions into
a workpiece such as a piece of steel, sheet metal, or other workpiece,
includes a guide body in which a stamp driver is slidably mounted for
being driven downwardly toward the workpiece by a punch press ram which
is a standard part of a high speed commercial punch press. A
multicharacter marking stamp is supported at the lower end of the stamp
driver for reciprocal movement therewith. The marking stamp includes
multicharacter wheels that are rotated automatically during operation for
advancing characters in sequence responsive to the movement of a
character advancing arm. At least one character stamp operating lever is
operatively associated with the punch press tool for articulation
responsive to motion imparted to the tool by the ram. The lever has an
operating element that is operatively associated with the character
advancing arm of the multicharacter stamp for indexing the arm to enable
successive characters thereof to be placed in an operating position
responsive to a stroke of the punch press ram.

Claims:

1. A punch press tool for stamping successive multicharacter impressions
into a workpiece comprising,a guide body adapted to be mounted upon a
punch press for being positioned beneath an operating ram of the punch
press,a stamp driver slidably mounted relative the guide body for being
driven downwardly by a ram of the punch press,a multicharacter marking
stamp supported on the tool for reciprocal movement thereon,said marking
stamp having multicharacter wheels adapted to rotate for sequentially
advancing raised characters thereon responsive to the movement of a
character advancing arm, p1 a stamp lever assembly having at least one
character stamp operating lever operatively associated with the punch
press tool for articulation responsive to movement imparted thereto by a
stroke of the punch press ram,said lever assembly also being operatively
associated with the character advancing arm of the marking stamp for
indexing the arm to sequentially position successive characters thereof
responsive to a stroke of the punch press ram and,each downward stroke of
the ram drives successive raised characters of the marking stamp that are
in an operative position into the workpiece to provide an impression of
the characters therein.

2. The punch press tool of claim 1 wherein the tool includes a return
spring connected to the actuator arm of the stamp for advancing the
character wheel of the stamp and the stamp lever assembly is operatively
associated with the character advancing arm for forcing the character
advancing arm to a refracted position against the tension of said return
spring.

3. The punch press tool of claim 1 wherein a stamp lever assembly includes
a pair of operating levers including a driven lever and a driving lever
that is positioned to press against the driven lever, each of the levers
are pivotally connected to the stamp driver, the driving lever is
pivotally connected to the guide body and the driven lever is operatively
associated with the character advancing arm of the marking stamp.

4. A punch press tool of claim 1 wherein the stamp lever assembly includes
a driving lever having an outer end pivotally connected to the guide
body, a central end operatively associated with one end of a driven lever
and a pivotal connection to the stamp driver intermediate the ends
thereof, said driven lever has an end portion opposite said one end that
is operatively associated with the character advancing arm of the stamp
and an intermediate pivotal connection to the guide body and said free
end of the driven lever is free to pivot upwardly when the stamp driver
is forced downwardly through the guide body of the tool for operating
said character stamp.

5. A punch press tool for stamping successive multicharacter impressions
into a workpiece comprising,a guide body adapted to be mounted upon a
punch press for being positioned beneath an operating ram of the punch
press,a stamp driver slidably mounted in the guide body for being driven
downwardly by a ram of the punch press,a multicharacter marking stamp
supported on the tool for reciprocal movement thereon,said marking stamp
having multicharacter wheels adapted to rotate for sequentially advancing
raised characters thereon responsive to the movement of a character
advancing arm,a stamp lever assembly having at least one character stamp
operating lever connected between the guide body and the stamp driver for
articulation responsive to relative motion therebetween,said lever
assembly being operatively associated with the character advancing arm of
the marking stamp for indexing the arm to sequentially position
successive characters thereof responsive to a stroke of the punch press
ram and,a downward stroke of the ram drives one or more raised characters
of the stamp that are in an operative position into the workpiece to
provide an impression of the characters therein,the punch press tool
includes a return element connected to the actuator arm of the marking
stamp for advancing a character wheel of the stamp and the stamp lever
assembly is operatively associated with the character advancing arm for
forcing the character advancing arm to a refracted position against the
tension of said return element.

6. The punch press tool of claim 5 wherein a stamp lever assembly with a
pair of operating levers including a driven lever and a driving lever
that is positioned to press against the driven lever, each of the levers
are pivotally connected to the stamp driver, the driving lever is
pivotally connected to the guide body, and the driven lever is
operatively associated with the character advancing arm of the marking
stamp and the length of at least one of said levers is selected to enable
the actuator arm to move a predetermined distance.

7. A punch press tool of claim 5 wherein the stamp lever assembly includes
a driving lever having an outer end pivotally connected to the guide
body, a central end operatively associated with one end of a driven lever
and a pivotal connection to the stamp driver intermediate the ends
thereof, said driven lever has an end portion opposite said one end that
is operatively associated with the character advancing arm of the stamp
and an intermediate pivotal connection to the stamp driver and said free
end of the driven lever is free to pivot upwardly when the stamp driver
is forced downwardly through the guide body of the tool for operating
said character stamp.

8. A punch press tool for stamping successive multicharacter impressions
into a workpiece comprising,a guide body adapted to be mounted upon a
punch press for being positioned beneath an operating ram of the punch
press,a stamp driver slidably mounted relative to the guide body for
being driven downwardly by a ram of the punch press,a multicharacter
marking stamp supported on the tool for reciprocal movement thereon,said
marking stamp having multicharacter wheels adapted to rotate for
sequentially advancing raised characters thereon responsive to the
movement of a character advancing arm,a stamp lever assembly having at
least one character stamp operating lever connected between the guide
body and the stamp driver for articulation responsive to relative motion
therebetween,said lever assembly being operatively associated with the
character advancing arm of the marking stamp for indexing the arm to
sequentially position successive characters thereof responsive to a
stroke of the punch press ram,a downward stroke of the ram drives one or
more raised characters of the stamp that are in an operative position
into the workpiece to provide an impression of the characters therein
andsaid tool includes a tool extension control for changing the distance
that the character stamp extends below the ram, said control comprising a
height adjustment member for changing the length of the tool between the
upper end of the stamp driver and the character stamp to thereby
establish the maximum distance that the characters of the character stamp
are carried downwardly by the operation of the ram.

9. The punch press tool of claim 8 wherein the extension control is
operatively connected to a locking member for retaining the extension
control in a selected position.

10. The punch press tool of claim 8 wherein the tool includes a return
element connected to the actuator arm of the stamp for advancing a
character wheel of the stamp and the stamp lever assembly is operatively
associated with the character advancing arm for forcing the character
advancing arm to a retracted position against the force of said return
element.

11. The punch press tool of claim 8 wherein a stamp lever assembly with a
pair of operating levers including a driven lever and a driving lever
that is positioned to press against the driven lever, each of the levers
are pivotally connected to the stamp driver, the driving lever is
pivotally connected to the guide body and the driven lever is operatively
associated with the character advancing arm of the marking stamp.

12. A punch press tool of claim 8 wherein the stamp lever assembly
includes a driving lever having an outer end operatively associated with
the guide body, a central end operatively associated but devoid of a
physical connection with one end of a driven lever and has a pivotal
connection to the stamp driver intermediate the ends thereof, said driven
lever has an end portion opposite said one end that is operatively
associated with the character advancing arm of the stamp and an
intermediate pivotal connection to the stamp driver and said free end of
the driven lever is adapted to pivot upwardly when the stamp driver is
forced downwardly through the guide body of the tool for operating said
character stamp.

13. A punch press tool for stamping successive multicharacter impressions
into a workpiece comprising,a guide body adapted to be mounted upon a
punch press for being positioned beneath an operating ram of the punch
press,a stamp driver slidably mounted in the guide body for being driven
downwardly by a ram of the punch press,a multicharacter marking stamp
supported on the tool for reciprocal movement thereon,said marking stamp
having multicharacter wheels adapted to rotate for sequentially advancing
raised characters thereon responsive to the movement of a character
advancing arm,a stamp lever assembly having at least one character stamp
operating lever that is operatively associated with the character
advancing arm of the marking stamp for indexing the arm to sequentially
position successive characters thereof responsive to a stroke of the
punch press ram,a downward stroke of the ram drives one or more raised
characters of the stamp that are in an operative position into the
workpiece to provide an impression of the characters therein,the punch
press tool includes a return element connected to the actuator arm of the
stamp for advancing a character wheel of the stamp and the stamp lever
assembly is operatively associated with the character advancing arm for
forcing the character advancing arm to a retracted position against the
force of said return element andsaid stamp lever assembly includes a pair
of operating levers including a driven lever and a driving lever that is
positioned to press against the driven lever, each of the levers are
pivotally connected to the stamp driver, the driving lever is pivotally
connected to the guide body and the driven lever is operatively
associated with the character advancing arm of the marking stamp.

14. The punch press tool of claim 13 including a tool length control for
adjusting the distance between a top end of the tool and a lower end of
the marking stamp to regulate the depth of a stamped impression into the
workpiece and to accommodate workpieces of various thicknesses.

15. The apparatus of claim 1 wherein the relative positions of the marking
stamp and the lever assembly can be changed for disengaging the marking
stamp character advancing arm from the lever assembly.

Description:

[0001]This invention relates to the punch and die art and more
particularly to a punch press stamping tool for marking a workpiece with
a stamped impression of numbers or letters in its surface.

BACKGROUND OF THE INVENTION

[0002]In the punch and die art and particularly in the field of high-speed
automated forming and punching equipment for punching and forming sheet
material, e.g., sheet metal and especially in the case of automated
turret punch presses, the punch presses are operated by computer to
rapidly perform a series of punching or forming operations. These punch
presses which by themselves form no part of the present invention are
typically provided with an upper turret and a lower turret that rotate
and are indexed intermittently between punching operations. The turrets
may, for example, hold as many as a dozen or more separate punches such
as hole punches that are used one after another for performing given
operations. When a punch is struck from above by the ram of the punch
press, the punch element or punch insert is driven downwardly through the
workpiece to perform the punching or forming operation. When released,
the punch insert is retracted by a spring provided in the punch assembly.

[0003]While there have been several attempts to provide a satisfactory
marking tool for punch presses, the prior tools are provided with
characters that must be changed manually or in other equipment are able
to make an impression of only one letter or number at a time. U.S. Pat.
No. 5,993,090, for example, describes a marking punch provided with
twelve letters, each of which is punched separately. So, for example, to
punch the number 2007 would require four punch strokes and some mechanism
for rotating the punch shaft between strokes but none is provided. U.S.
Pat. No. 4,397,233 describes an automatic numbering assembly that instead
of making an impression into the workpiece, transfers ink from an ink
roller to a package as the drum rotates. Thus, the patented device is not
suitable for making an impression in metal nor for being operated by the
reciprocating ram of a punch press. A multicharacter punch numbering
stamp has been made for a punch press by the Conic Company Ltd. of
Okayama, Japan, but the digits of the numbering wheel must be
individually set by hand between stamping operations. Thus each time the
machine is run, it will continue to stamp the same number until the press
is stopped and the wheels are rotated by hand to provide a new number.
While numbering devices themselves are available commercially, there is
no way to operate them using a high speed computer controlled punch
press. Consequently, as far as the applicants were able to determine, no
punch press tool for stamping successive multicharacter impressions into
a workpiece has been developed that is able to be actuated by the rapidly
reciprocating ram of an automated punch press and is capable of
successively stamping numbers or other characters in sequence into a
workpiece such as a sheet of metal.

[0004]In view of these and other deficiencies of the prior art, it is one
object of the present invention to find a way to enable a high speed
computer operated punch press to reliably impress alphanumeric characters
or other indicia a selected depth into the surface of a workpiece and to
advance the characters each cycle of the press ram.

[0005]Another object of the invention is to provide a device of the kind
described in which the characters to be stamped are extended out below
the unit but not far enough to strike objects unintentionally as the
punch press operates and are preferably able to accommodate workpieces of
various thicknesses.

[0006]These and other more detailed and specific objects and advantages of
the present invention will be better understood by reference to the
following figures and detailed description which illustrate by way of
example but a few of the various forms of the invention within the scope
of the appended claims.

SUMMARY OF THE INVENTION

[0007]Briefly, the present invention provides a punch press tool for
stamping successive multicharacter impressions in a workpiece such as a
piece of steel, sheet metal, or other workpiece, that includes a guide
body in which a stamp driver that is slidably mounted for being driven
downwardly toward the workpiece by a punch press ram which is a standard
part of a high speed commercial computer operated punch press. A
multicharacter marking stamp is supported at the lower end on the stamp
driver for reciprocal movement therewith. The marking stamp includes
multicharacter wheels that are rotated automatically during operation for
advancing characters in sequence responsive to the movement of a
character advancing arm. At least one character stamp operating lever is
operatively associated with the advancing arm of the stamp driver and is
arranged for articulation responsive to the motion of the punch press
tool. On the operating lever is a pressure element that is operatively
associated with the character advancing arm of the multicharacter stamp
for indexing the arm to sequentially position successive characters in an
operative position responsive to a stroke of the punch press ram that
drives the characters of the marking stamp into the workpiece.

BRIEF DESCRIPTION OF THE FIGURES

[0008]FIG. 1 is a bottom perspective view of a punch press tool in
accordance with the invention, showing its marking stamp in the operating
(extended) position.

[0009]FIG. 2 is a fragmentary view of FIG. 1 with the stamp in its raised
(inoperative) position.

[0010]FIG. 3 is a top perspective view of the press tool of FIG. 1.

[0011]FIG. 4 is a central vertical sectional view of the tool of FIGS. 1-3
with the stamp in the up or retracted position.

[0012]FIG. 5 is a view similar to FIG. 4 with the stamp in the down or
operating position.

[0013]FIG. 6 is a bottom exploded perspective view of the tool of FIGS.
1-5.

[0015]FIG. 8 is a partial vertical sectional view similar to FIG. 4 but
with the character stamp removed.

[0016]FIG. 9 is a partial vertical sectional view similar to FIGS. 5 and 8
showing. diagrammatically another embodiment of the invention with a
single stamp operating lever.

[0017]FIG. 10 is a plan view of a stamping made with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0018]In FIGS. 1-3 the punch press tool according to the invention,
indicated generally by the numeral 10 comprises two major parts; a guide
body 18 and a stamp driver 12 of cylindrical shape having a cylindrical
boss 12a at its upper end that is bored at 12b to receive an adjustable
striker head 12c of cylindrical shape which is screw threaded into the
lower portion of the stamp driver by means of threads 12d. The lower part
of the stamp driver 12 is slidably mounted in a vertically disposed bore
16 in the guide body 18 which is provided on its outer surface with
circumferentially spaced apart longitudinally extending keyways 18a for
holding it at the proper angle about a vertical axis.

[0019]FIGS. 4 and 5 show how during use, the stamping tool 10 is mounted
for operation on the upper turret 20 of a punch press by being placed
within a circular tool holder 22 of conventional well known construction
that is itself supported within an adapter ring 24. The tool 10 is
supported on the tool holder 22 by means of lifter springs 22a. In
operation, the upper punch press turret 20 rotates rapidly on a vertical
axis (not shown) which is behind the tool 10 to place various tools in
alignment with the punch ram 26 of the punch press as the ram
reciprocates on a vertical axis indicated by an arrow 28 to strike
whichever tool mounted on the turret is located in the punching station
beneath the reciprocating ram 26. One or more keys 30 in the tool holder
22 maintain the guide body 18 in the correct angular position about a
vertical axis during operation. Between the stamp driver 12 and the guide
body 18 are mounted several compression springs 5 for elevating the stamp
driver between strokes. The stamp driver 12 has at its lower end a stamp
driver end plate 12e which is held in place by bolts 13 and a lever
bracket 12f which is secured in place by a bolt 15.

[0020]Other punch assembly units of various designs suited for use in a
high speed punch press are described in U.S. Pat. Nos. 5,054,347 and
6,895,787 as well as U.S. applications Ser. Nos. 11/238,380 and
11/583,430 which are all incorporated herein by reference.

[0021]Characters provided on a marking stamp 52 are advanced by an
operating lever assembly that in FIGS. 1-8 comprises a driving lever 42
and a driven lever 46. Attached to the lower end of the lever bracket 12f
of stamp driver 12 by a set screw or other fastener are horizontal pivot
pins 40 upon which is pivotally mounted the generally U-shaped character
stamp operating lever 42 (the driving lever) the outer end of which is
pivotally secured to a horizontally disposed pivot pin 44 that is carried
by the guide body 18. As seen best in FIGS. 6 and 7, the inner free ends
of the U-shaped lever 42 have upwardly facing convex working surfaces 42a
that are engaged as shown in FIG. 8 with the free end at the right of a
second stamp operating lever 46 (a driven lever) which is mounted for
pivotal movement on horizontal pins 48 also carried on bracket 12f (FIG.
6) of the stamp driver 12. Thus, as lever 42 pivots counterclockwise its
working surface 42a allows lever 46 to pivot in the opposite direction
but lever 42 is not physically connected to lever 46. The lever 46
extends from pivots 48 toward the left at 46a and has on its lower
surface an operating pad or other pressure applying element 46c that is
engaged during use with the upper surface of a roller 50 which is secured
to the free end of a character advancing arm 51 of the multicharacter
marking stamp 52 (shown in dotted lines in FIG. 5) which is itself
affixed to the lower end of the stamp driver 12 by a draw bolt 54 so that
during operation as the ram 26 of the punch press reciprocates, its
engagement with the striker head 12c drives the stamp driver 12
downwardly through the guide body 18 thereby forcing the marking stamp 52
downwardly and into contact with a workpiece 60 which is supported on an
anvil 62 so as to form an impression in its upper surface.

[0022]It can be seen that the invention allows the lengths of the lever
arms of levers 42 and 46 to be chosen so as to move the operating pad 46c
any desired distance as the ram and the stamp driver 12 reciprocate;
whatever distance is correct for a particular actuator arm 51.

[0023]The marking stamp 52 can be of any suitable commercially available
construction such as a series 2000 automatic numbering head manufactured
by the Pryor Company Ltd. of Sheffield England. Other suitable automatic
sequential numbering stamps are manufactured by the Numberall Stamp &
Tool Company of Sangerville, Me., USA, and by Mecco Partners LLC of
Ingomar, Pa., USA. These multicharacter marking stamps are each provided
with multicharacter e.g. digital wheels 52a that are rotated
incrementally during operation for sequentially advancing raised
characters to place a series of letters or numbers located in an
operating position at the bottom of the stamp so that the numbers or
other characters increase or advance in a predetermined sequence
responsive to the indexing of a character advancing arm 51 which swings
up and down during operation through an arc so as to advance the number
wheels one character at a time, each time the arm 51 is indexed upwardly
by one or more return elements for biasing the arm 51 upwardly as
pressure applied by the driven lever is released. The return element can
be of any suitable construction such as a weight, compressed air,
hydraulics, an electric solenoid, rubber or the like such as a pair of
return springs 53 that are connected between the arm 51 and the top of
stamp 52. The return spring 53 serves to advance the character wheels 52a
of the stamp 52, whereas the stamp lever assembly forces the character
advancing arm in the opposite direction (downwardly) to a retracted
position against the tension of the return spring as the stamp driver 12
moves upwardly. Thus, in operation a downward stroke of the ram 26 drives
the marking stamp and one or more of the raised characters that are in an
operative position at the lower end of the stamp into the workpiece 60 to
provide an impression of those characters in its upper surface typically
with sequential numbers in successively stamped parts 80 (FIG. 10).

[0024]Secured to the lower end of the guide body 18 by means of screws or
other suitable fasteners is a stripper 18b having a rectangular opening
18c for the character wheels 52a of the stamp 52. The stripper 18b serves
to hold the workpiece 60 in place as the impression is made by the
character wheels of the stamp 52. FIGS. 1 and 5 show how the character
wheels 52a are extended downwardly and out through the opening 18c a
short distance but not far enough to strike other objects as the press
operates.

[0025]By manually retracting the height adjustment locking button 14, then
raising or lowering the striker head 12c by rotating it manually so as to
screw it up or down on the threads 12b on the stamp driver 12, the
distance that the raised characters on the character wheels 52a protrudes
through the opening 18c (FIGS. 1 and 5) can be accurately set at any
selected amount to thereby accommodate workpieces 60 of any thickness
while also controlling the depth of the character impressions into the
surface of the workpiece 60.

[0026]To inactivate the stamp 52, the draw bolt 54 is disconnected from
the stamp 52 which is removed. The driven operating lever 46 is then
rotated 180° about pivot 48 to separate actuator advancing arm 51
from the driven operating lever 46. Stamp 52 is then replaced and the
bolt 54 is connected. Operating lever 46 is then rotated to a position
where it can rest on the stripper 18b i.e. on the opposite side of roller
50. This enables the stamp 52 to repeatedly impress the same number or
other character into the workpiece 60 whenever desirable or necessary.

[0027]Refer now to FIG. 9 which illustrates diagrammatically another
possible operating lever arrangement employing a single operating lever
27 having a fulcrum pivot 27a that is supported on a flange 19 which is
connected to the guide body 18 and a movable pivot 27b at its outer end
that is in turn connected to a modified lever bracket 12g spaced outboard
of the fulcrum pivot 27a so as to cause operating surface 27c of the
lever 27 to be raised when the stamp driver 12 is lowered. The springs 53
are then able to advance the characters on wheels 52a sequentially to the
next appropriate number or letter as pressure on arm 51 is removed. The
use of two levers 42 and 46 rather than one does, however, provide
unexpected benefits; lever 46 can swing through a greater arc than a
single lever and can have the same radius as arm 51. We also found that
using two levers allows the stamp to be removed and the pressure pad 46c
then placed in a position where it is inactive. Thus, the use of two
levers rather than a single lever makes it possible to inactivate the
stamp advancing mechanism when desired since it enables lever 46 to be
moved to the opposite side of roller 50 i.e. below the roller where it
cannot move the roller since in that position it is not in contact with
working surface 42a of lever 42.

[0028]The invention provides outstanding results and unique capabilities.
It was found that it is able to actuate a stamp 52 with a relatively
short stroke of the ram, typically about 7 mm., even though the actuator
arm 51 for the multicharacter stamp 52 must move much further; about 21
mm. while at the same time providing a way to inactivate or disengage the
character stamp advancing mechanism when desired so that the stamp is
able, when necessary, to continue stamping the same number or other set
of characters. It is also able if and when necessary to index the stamp
to the next digit or letter between strokes and not during the punching
operation, in other words, the character stamp can be advanced during the
upward stroke of the punch. Furthermore, the character stamp when in the
operating position does not extend too far from the lower end of the tool
where it could create an obstruction, i.e., where it might strike other
objects as the tool is moved rapidly from one position to another while
the press operates. In addition, it is capable of moving the character
stamp actuator arm in the upward direction while a machine component (a
guide body sleeve surrounding the character stamp) moves the opposite
direction, i.e., downwardly. It is also able to regulate the stamp depth
and to accommodate workpieces of different thicknesses.

[0029]Many variations of the present invention within the scope of the
appended claims will be apparent to those skilled in the art once the
principles described herein are understood.